How do I invoke native actions from inside my in-app message?

If you want to bridge things into the native app, this is commonly done by registering protocol handlers. Have the app register a protocol handler if it doesn't already, which would make it handle all URLs for a certain path, like yourapp://example/example.

If you wanted to deep link into your settings page, for instance, you could do it by having the call to action of your creative specify yourapp://settingsPage as the target URI.

Similarly, on the app side, you would write code that would register your app to intercept this URL, parse it, and do something interesting with the payload (in this case, navigate to the settings page).